Without limiting the scope of the invention, its background is described in connection with Raman sensors.
One example is taught in U.S. Pat. No. 7,879,625, issued to Boss for the preparation of SERS substrates on silica-coated magnetic microspheres. Briefly, this patent discloses improved surface-enhanced Raman scattering (SERS) substrates that are said to comprise chemically-derivatized magnetic microparticles complexed with metal colloidal particles or substrates. The SERS substrates are said to permit collection, detection, measurement, and/or analysis of analytes present at concentrations ranging parts per trillion to parts per billion. The compositions, methods, and devices taught are also said to provide for rapid and/or sensitive detection of chemical compounds of interest present in small concentrations. The SERS substrates on silica-coated magnetic microspheres are said to allow the detection of trace samples including, for example, BTEX (benzene, toluene, ethylbenzene, and xylenes), chlorinated solvents, TNT, nerve agents, blister agents, metal ions, anions, antigens, peptides, nucleic acids, spores, fungi, viruses, and bacteria.
Two more examples are taught in U.S. Pat. Nos. 7,829,348 and 7,824,926, issued to Porter, et al., for Raman-active reagents and the use thereof. Briefly, these patents are said to provide Raman-active reagents for use in biological and other applications, methods and kits for their use, and manufacture. Porter teaches a Raman-active reporter molecule, a binding molecule, and a surface-enhancing particle that causes surface enhanced Raman scattering (SERS). The Raman-active reporter molecules and the binding molecules are affixed to the particle to give both a strong SERS signal and to provide biological functionality, e.g., antigen or drug recognition. The Raman-active reagents are said to function as an alternative to fluorescence-labeled reagents, and have the advantage of having: improved signal stability, sensitivity, and the ability to simultaneously detect several biological materials. The Raman-active reagents also said to have a wide range of applications, especially in clinical fields (e.g., immunoassays, imaging, and drug screening).
Another example is taught in United States Patent Application Publication No. 2013/0040292, filed by Fernandez Lopez, et al., and is directed to nanoparticle biosensor, method of preparing same and uses thereof. Briefly, this application is said to teach nanoparticle biosensors comprising: a magnetic core, a silica layer, one or more outer metal layers which can be of different types and deposited in an alternating manner and immobilized on the outer surface, and a layer of synthetic or natural organic or inorganic biosensor molecules that can bind to biomolecules. The invention also relates to a method of obtaining the nanoparticle biosensors as well as to the different uses thereof.